Apparatus, system, and method for diagnosing initiators in airbag systems

ABSTRACT

A method for diagnosing aircraft airbag initiators in air bag systems includes: providing a diagnostic circuit per aircraft seat, the diagnostic circuit being in a normally off condition and enabled by a user activation; providing a power supply independent of aircraft power; providing a momentary switch; providing a visual indicator; receiving a signal indicating user activation of the momentary switch; and responsive to receiving the signal: completing a circuit, regulating a current into the diagnostic circuit to prevent a squib from firing during diagnostic evaluation; detecting a voltage; and providing feedback to the user.

CROSS-REFERENCE TO RELATED APPLICATIONS

This U.S. Non-Provisional patent application is a continuationapplication of, and claims the benefit of, currently pending U.S.Utility patent application Ser. No. 15/294,947, filed on Oct. 17, 2016,which is a continuation application of, and claims the benefit of U.S.Utility patent application Ser. No. 14/702,714, filed on May 2, 2015,now U.S. Pat. No. 9,499,115, which is a non-provisional of the nowexpired U.S. Provisional Patent Application No. 61/987,490, filed on 2May 2014; all of which are incorporated by reference as if fully setforth herein.

FIELD OF THE INVENTION

This invention relates generally to the field of electrical diagnosticequipment, devices, and systems and related methods and, morespecifically to systems and methods for diagnosing initiators in airbagsystems.

BACKGROUND

It is known in the art for airbag inflation systems to utilize a batteryor other power source to drive a circuit in order to fire an inflatorunder prescribed conditions, thereby inflating the airbag. The inflatoris fired when acceleration switches, used to detect an impact, allow thecurrent from the battery or other power source to flow through thecircuit to an initiator, or squib, charges the initiator, which thenignites the inflator.

The integrity, or “health” of the circuit and, most importantly, of thesquib, is paramount to the proper operation of the airbag in a crashevent. If any part of the circuit fails, or if the squib itself fails,then the inflator will not fire and the airbag will not deploy.

The problem is that these circuits are typically “blind” systems. Thereis often no simple way to test the integrity of the system withoutinadvertently deploying the airbag.

Previous attempts to address this problem have incorporated diagnosticmeans that impose a power drain on the system while inactive. Forbattery powered airbag systems, such as those employed in aircraft, itis not desirable to have a diagnostic means that also drains the batterywhile not in use. Current attempts in the art have suffered from thisproblem where the continuous current draw drains the battery, renderingthe firing system inoperable when it is needed the most—in a crashevent. Other attempts in the prior art include a required second sourceof electrical energy in the monitoring and diagnostic circuit inaddition to the primary electrical energy source used to power thefiring system.

Other attempts to diagnose the integrity of the firing system fall shortbecause they are not able to detect shorts or opens at individualsquibs. This is a problem in systems where one electronic control module(ECM) may control the firing of multiple airbags. This is typically thesituation in airbag systems for aircraft where one ECM may be used todeploy multiple airbags, one or more on each of a row of seats.

It would, therefore, be desirable to have a system and related methodfor diagnosing initiators in airbag systems where one, or more than one,initiator may be diagnosed individually, shorts or opens may bedetected, with no power drain while inactive and without the need for asecond source of electrical energy.

While certain aspects of conventional technologies and methods in therelevant art have been discussed to facilitate disclosure of theinvention, Applicant in no way disclaims these technical aspects ormethods, and it is contemplated that the claimed invention may encompassone or more of the conventional technical aspects or methods discussedherein.

In this specification, where a document, act, or item of knowledge isreferred to or discussed, this reference or discussion is not anadmission that the document, act, or item of knowledge or anycombination thereof was, at the priority date, publicly available, knownto the public, part of common general knowledge, or otherwiseconstitutes prior art under the applicable statutory provisions; or isknown to be relevant to an attempt to solve any problem with which thisspecification is concerned.

SUMMARY

In this specification and in the appended claims and drawings, words andphrases have the meanings commonly attributed to them in the relevantart except as otherwise specified herein.

In this specification and in the appended claims and drawings,“initiator”, including grammatical equivalents, singular and plural, isa pyrotechnic device, comprising a conductor and a combustible materialthat activates under a predetermined current pulse and ignites thecombustible material thereby initiating a gas generator which inflatesthe airbag. The term “squib” is used interchangeably with “initiator.”

The present invention may address one or more of the problems anddeficiencies of the prior art discussed above. However, it iscontemplated that the invention may prove useful in addressing otherproblems and deficiencies in a number of technical areas. Therefore theclaimed invention should not necessarily be construed as limited toaddressing any of the particular problems or deficiencies discussedherein.

In view of the foregoing, an embodiment herein provides a novel systemand related method for diagnosing initiators in air bag systems.Specifically, an embodiment of the system comprises a diagnostic circuitelectrically connected between the acceleration switches and the one ormore squib, that is user-activated via a momentary switch, and withuser-feedback, wherein a user can diagnose the health of the one or moresquib with no power drain while inactive.

An embodiment of a method related to the system comprises activating amomentary switch, completing a circuit whereby a diagnostic circuit mayfunction, indicating to the user that the diagnostic circuit isfunctioning, regulating the current into the diagnostic circuit so thatthe squib does not fire, boosting the signal to a window comparator,detecting the desired voltage by the window comparator, giving feedbackto the user that the voltage is good, too high, or too low.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood with regard to the followingdescription, appended claims, and accompanying drawings where:

FIG. 1 illustrates a schematic view of an electronic control moduleapparatus with an integrated diagnostics system according to anembodiment herein;

FIG. 2 illustrates a schematic view of a system for diagnosinginitiators in airbag systems according to an embodiment herein;

FIG. 3 illustrates a schematic view of multiple diagnostic systemsutilizing FET switches according to an embodiment herein; and

FIG. 4 illustrates a flow chart of the steps associated with a methodfor diagnosing initiators in air bag systems with no power drain whileactive according to an embodiment herein.

DESCRIPTION

In the Summary of the Invention above, in the Description and appendedClaims below, and in the accompanying drawings, reference is made toparticular features of the invention. It is to be understood that thedisclosure of the invention in this specification includes all possiblecombinations of such particular features. For example, where aparticular feature is disclosed in the context of a particular aspect orembodiment of the invention, or a particular claim, that feature canalso be used, to the extent possible, in combination with and/or in thecontext of other particular aspects and embodiments of the invention,and in the invention generally.

The term “comprises” and grammatical equivalents thereof are used hereinto mean that other components, ingredients, steps, etc. are optionallypresent. For example, an article “comprising” (or “which comprises”)components A, B, and C can consist of (i.e., contain only) components A,B, and C, or can contain not only components A, B, and C but also one ormore other components.

The term “at least” followed by a number is used herein to denote thestart of a range beginning with that number (which may be a range havingan upper limit or no upper limit, depending on the variable beingdefined). For example “at least 1” means 1 or more than 1. The term “atmost” followed by a number is used herein to denote the end of a rangeending with that number (which may be a range having 1 or 0 as its lowerlimit, or a range having no lower limit, depending upon the variablebeing defined). For example, “at most 4” means 4 or less than 4, and “atmost 40%” means 40% or less than 40%. When, in this specification, arange is given as “(a first number) to (a second number)” or “(a firstnumber)-(a second number),” this means a range whose lower limit is thefirst number and whose upper limit is the second number. For example, 25to 100 mm means a range whose lower limit is 25 mm, and whose upperlimit is 100 mm.

While the specification will conclude with claims defining the featuresof embodiments of the invention that are regarded as novel, it isbelieved that the invention will be better understood from aconsideration of the following description in conjunction with thefigures, in which like reference numerals are carried forward.

The embodiments herein and the various features and advantageous detailsthereof are explained more fully with reference to the non-limitingembodiments that are illustrated in the accompanying drawings anddetailed in the following description. Descriptions of well-knowncomponents and processing techniques are omitted so as to notunnecessarily obscure the embodiments herein. The examples used hereinare intended merely to facilitate an understanding of ways in which theembodiments herein may be practiced and to further enable those of skillin the art to practice the embodiments herein. Accordingly, the examplesshould not be construed as limiting the scope of the embodiments herein.Specifically, component names, types, and values, as depicted in theexemplary schematic diagrams, are not intended to limit the scope of thepresent invention and are presented only as possible embodiments.

We refer now to the various figures in general, and to FIG. 1 inparticular. We discuss here an electronics control module (ECM) 100 forsensing a crash event and initiating an inflation sequence for one ormore airbags with an integrated system for diagnosing one or moreinitiators 140, as described in the various embodiments herein. The ECM100, according to an embodiment, may include a housing 150 enclosing oneor more circuit boards (not illustrated for simplicity), to which may beelectrically connected one or more wire harnesses 170 which themselvesare electrically connected to one or more squibs 140. The ECM 100further includes an electrical power source 160, such as a battery, andevent sensing means such as acceleration switches 110 and 115 which arenormally open but close to complete the circuit upon a predeterminedevent, such as a g-shock, or force, as in a crash event.

Referring now to FIG. 2 and the drawings in general, embodiments of thepresent invention, as described here, and in the appended claims anddrawings, include, but are not limited to, a system 200 for diagnosingthe electrical integrity of a squib 140 and wire harness 170 activatedby an electronics control module 100 comprising a momentary switch 130which, when closed, connects a system ground 210 to an ECM ground 220,completing a circuit for a current to flow from the ECM to the system inorder for the diagnostic circuit 120 to function. Resistors 230, orother current regulating means as are known in the art, are electricallyconnected in the diagnostic circuit 120 at a current high input 122 anda current low input 124 in order to regulate the current into thediagnostic circuit 120 to ensure that the squib 140 does not fire duringdiagnostics. It should be appreciated by one skilled in the art that theresistor 230 value is to be chosen based upon the squib 140 currentrequirements. A signal booster 240 is electrically connected to thediagnostic circuit 120 at the point of electrical connection to theharness 170 and squib 140. This signal booster 240 amplifies the signalto a window comparator 250. The window comparator 250 is electricallyconnected to the output of the signal booster 240 and determines if thevoltage across the harness/squib is good, too high, or too low. One ofskill in the art will recognize that the window comparator may includeresistors and op-amps that are tuned to detect the desired voltage. Thewindow comparator 250 includes outputs electrically connected toindicators 260, such as LEDs, to indicate to the user if the voltage isgood, high, or low, thereby indicating to the user if the squib andharness integrity is within the desired parameters.

We refer now to FIG. 3 in particular and to the drawings in general. Ina preferred embodiment of the system for diagnosing initiators in airbagsystems, where an ECM is used to fire airbags, the system 300 comprisesone or a plurality of diagnostic circuits 120, wherein an at least onediagnostic circuit 120 corresponds to an at least one squib 140. The atleast one diagnostic circuit 120 should preferably be electricallyconnected between the ECM event detection circuitry 310 and the outboundwire harness 170, which includes the squib or squibs 140. The ECM eventdetection circuitry 310 includes at least a power source 160, anacceleration switch 110 electrically connected to the high voltageoutput of the power source, and an acceleration switch 115 electricallyconnected to the low voltage output of the power source. The diagnosticcircuit 120 comprises a momentary switch which, when closed, connects asystem ground to an ECM ground, completing a circuit for a current toflow from the ECM to the system in order for the diagnostic circuit tofunction. An LED, electrically connected between the momentary switchand the system ground, is included to indicate that the diagnosticcircuit is receiving power and is ready to diagnose. Resistors, or othercurrent regulating means as are known in the art, are electricallyconnected in the diagnostic circuit at a current high input and acurrent low input in order to regulate the current into the diagnosticcircuit to ensure that the squib does not fire during diagnostics. Oneskilled in the art should appreciate that the resistor value is to bechosen based upon the squib current requirements. A signal booster iselectrically connected to the diagnostic circuit at the point ofelectrical connection to the harness and squib. This signal boosteramplifies the signal to a window comparator. The window comparator iselectrically connected to the output of the signal booster anddetermines if the voltage across the harness/squib is good, too high, ortoo low. One of skill in the art will recognize that the windowcomparator may include resistors and op-amps that are tuned to detectthe desired voltage. The window comparator includes outputs electricallyconnected to indicators, such as LEDs, to indicate to the user if thevoltage is good, high, or low, thereby indicating to the user if thesquib and harness integrity is within the desired parameters.

In a preferred embodiment of a method related to the system, as shown inFIG. 4, the method 400 comprises activating a momentary switch 410,completing a circuit 420 whereby a diagnostic circuit may function,indicating to the user 430 that the diagnostic circuit is functioning,regulating the current 440 into the diagnostic circuit so that the squibdoes not fire, boosting the signal 450 to a window comparator, detectingthe desired voltage 460 by the window comparator, giving feedback 470 tothe user that the voltage is good, too high, or too low.

Further embodiments of the present invention may include, but are notlimited to, systems with multiple diagnostic circuits. Embodiments ofthe present invention may take advantage of the scalability of theinvention and are not limited as to the number of squibs or diagnosticcircuits that may be employed in a given embodiment. For example, in thecase of aircraft airbag systems, it would be desirable to utilize anembodiment of the present invention comprising one system to diagnoseone six-passenger row of seats. This embodiment would comprise sixdiagnostic circuit systems in order to individually diagnose each of thesix airbag squibs. Alternatively, the embodiment may further comprisethe six-circuit diagnostic system as above, but utilizing only oneuser-activated momentary switch in order to get feedback on the healthof all six squibs and harnesses individually, but with only one userinput.

Referring to FIG. 3, further embodiments of the present invention mayinclude, but are not limited to, the use of electrically connected means270 to prevent back-flow of current. Such means may be chosen fromcomponents including diodes and FET switches. Preferred embodiments ofthe present invention include the use of FET switches 270 to prevent theback-flow of current, but with a small voltage drop. It is contemplatedby the invention that there may be some cases in which a highresistance, or even an open connection, may occur within a trigger loopin a multi-squib system. In this case, embodiments of the presentinvention may include additional circuitry to balance the currentbetween the squib loops when using an active component, such as a FET,which does not separate the squib loop physically in order to ensureproper diagnostic function. One skilled in the art will recognize thatthis may be accomplished by various means, for example, by a transistornetwork. The use of balancing circuits in embodiments of the inventionprovides means by which each squib, or inflator loop, can be accuratelychecked for shorts or opens within a specified range without affectingthe other inflator loops.

Further embodiments of the present invention may include, but are notlimited to, user-activation of the diagnostic circuit via momentaryswitches that are a pushbutton. Other embodiments contemplated mayinclude, but are not limited to, user-activation of the diagnosticcircuitry via an input signal from a user such as, but not limited to,an input signal from processor such as a PC or handheld device, saidsignal being transmitted either wired or wirelessly.

Further embodiments of the present invention may include, but are notlimited to, user-feedback utilizing one or more LEDs. Other embodimentsof user feedback contemplated include, but are not limited to, wired orwireless output signals to be received by processor such as a PC orhandheld device, or even an audible tone.

It is further contemplated to be within the scope of the presentinvention that the diagnostic system disclosed herein may bemanufactured utilizing discrete components or also as an integratedcircuit (IC).

It will be appreciated that the devices, apparatus, and systemsdescribed above are set forth by way of example and not of limitation.Numerous variations, additions, omissions, and other modifications willbe apparent to one of ordinary skill in the art.

While particular embodiments of the present invention have been shownand described, it will be apparent to those skilled in the art thatvarious changes and modifications in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the following claims. The claims that follow are intended toinclude all such variations and modifications that might fall withintheir scope, and should be interpreted in the broadest sense allowableby law.

In light of the foregoing description, it should be recognized thatembodiments in accordance with the present invention can be realized innumerous configurations contemplated to be within the scope and spiritof the claims. Additionally, the description above is intended by way ofexample only and is not intended to limit the present invention in anyway, except as set forth in the claims.

What is claimed is:
 1. A method for diagnosing a plurality of aircraftairbag initiators in an aircraft airbag system, the method comprising:providing a diagnostic circuit per aircraft seat, each diagnosticcircuit electrically connected between an aircraft crash sensing meansand one of the plurality of aircraft airbag initiators, the diagnosticcircuit being in a normally off condition and enabled by a useractivation; providing a power supply, independent of aircraft power,electrically connected to each diagnostic circuit; providing a momentaryswitch; providing a visual indicator providing feedback to the user of ahealth of each of the plurality of aircraft airbag initiators, thevisual indicator configured to be operative once the user has activatedthe diagnostic circuit; receiving a signal indicating user activation ofthe momentary switch; and responsive to receiving the signal: completinga circuit for the diagnostic circuit to function, indicating to the userthat the diagnostic circuit is functioning; regulating a current intothe diagnostic circuit to prevent an aircraft airbag initiator fromfiring during diagnostic evaluation; boosting the signal to a windowcomparator; detecting a voltage by the window comparator; and providingfeedback to the user about the voltage.
 2. The method of claim 1 furthercomprising using an FET switch to prevent back-flow of electricalcurrent.
 3. The method of claim 1 further comprising using diodes toprevent back-flow of electrical current.
 4. The method of claim 1wherein providing the momentary switch comprises providing a pushbutton.